Chassis completion

Now, the chassis has been built to the stage where the drive train could be fitted. It is now time to complete the chassis with all remaining details and get it painted before we can turn my attention to the valve gear

What needs to be done?

• Add the brake rigging
• Build the cylinders and attach them to the frame
• Add the motion bracket
• Build the pickups and devise a way to to attach them to the frame
• Then prepare the chassis for painting
• Apply base coat
• Apply top coat
• Apply clear coat.
• Add a little weathering
• Apply dull coat

Let's get started!

Brake rigging

The brake rigging laid out

• Top: brake shoes on brake hangers, connected by a etched piece
• Middle: brake levers
• Bottom: brake rod with cylinder lever (right)

Note that the four brake sets are different and marked a, b, c, and d, with a being at the front of the frame (left on the photo) and the brake shoes pointing backwards. Prototypically only the first four axles have a single action brake shoe, the last axle has none.

The cylinder lever, the triangular part, goes into a slot that is more or less provided in the etch of the rear frame strengthener.

The slot is actually undersized and needs some serious opening up. As the metal is thick it is easier said than done.

After folding the brake shoe sets make sure to run a small solder fillet in the corner of the fold to strengthen the weak bend.

All brake shoe sets soldered in place. 

Observe them to be in the middle and upright. Small correction can be made with the wheels in place

Now the brake shoes are soldered in situ their position can be checked. They should never touch the wheel treads. Then the brake levers are soldered to the brake hangers (yellow). I did not solder the brake rod to the the brake levers yet (red).

This proved to be a good decision as some hangers needed so more adjustment than the slot in the brake rod provided for.

So I had to take all four levers off again, lengthen the slots in the brake rod with a piercing saw and bring it all back into place again.

During the adjustment I found the brake rod to be a bit too long so I cut it the off the cylinder lever. Once all adjustments were done I soldered the brake rod to the back of the cylinder lever. No one can tell!

Done!

Cylinder assembly

This is how the original kit parts for the cylinder were supposed to go together. I have two major objections.

• The crosshead will easily come off the slide bar. In hindsight I saw that the provided WD style drop link would provide for this.
• The crosshead is made of white metal, too soft for the job.

So I turned to Markits for parts and ordered a sets of milled crossheads and a set of four bar crossheads. I am aware that the WD locomotives did not have four bar crossheads, but in this case I prefer reliability over prototypical depiction. I am also aware that the Markits parts are made to suit the 1:76 scale requirements and I am building in 1:87, but again that is something I will accept for the sake of reliability.

The piston glands on the back of the rear cylinder cover are removed so the cylinder cover is completely plain. The hole for the piston is widened to accommodate the piston sleeve and this sleeve is soldered in place (80C white metal solder).

The sleeve has its own piston glands, so that is why I cut the original glands away in the first place.

The cylinder cover is first soldered to the outer of the two cylinder halves.

The inserted drill helps to check if the sleeve sits right straight into the cylinder.

The Blu-Tack is than carefully pried away and a bit of epoxy is worked behind the sleeve with a thin strip of brass. I used 0.25 mm to poke the glue into place. Take great care that the glue does not enter in to the open end of the sleeve on the right side.

Before glueing the slide bar into place it must be checked if a full stroke of the wheels can be accommodated

Full stroke to the rear. The cylinder is not sitting straight, do not worry, I will see to that when it is glued in placed.

And a full stroke to the front

The conclusion of the this test was that the slide bar could be pulled back a bit, away from the cylinder, and that it could indeed accommodate the full stroke. I also tweaked the slide bars so that the crosshead would slide in it solely on gravity.

The outer end of the slide bar is a 1.1 mm off centre relative to the middle of the piston, as demonstrated by the photo on the right. I soldered two strips of nickel silver to this outer end so that the whole assembly sits correctly in the cylinder.

Then the slide bar is glued into position.

Finally the inner cylinder half is glued. It may be necessary to take some material away form the innards as, again, the outer end of the slide bar has moved 1.1 mm further inwards.

Note that by handling the cylinder, and very much aided by dropping it onto the floor, the outer piston sleeve had become undone (yellow circle). Bending it back had the expected result: it broke off.

Done! At long last.

The puzzling with the replacement parts from Markits cost me a lot of time. The motion gear of the utmost importance for a good running locomotive and clearances are usually tight so any change you make from the standard kit most be considered with great caution. But I think it worked out well.

Both crossheads run lightly in the their slide bars. The bent outer sleeve was replaced by a scrap of brass rod (yellow circle).

The cylinders are one by one glued to the mainframe.

Next I turned my attention to the leading truck. It was intended in the kit that it would be attached to the round frame spacer which is drilled through. Of course I missed that detail and the hole is now point more or less forward instead of down and the whole lot is soldered rock solid.

So I bent a sheet of 0.5 mm nickel silver to fit over the spacer, soldered a nut in place and glued it with epoxy.

I shortened the truck arm correspondingly. I made a bush to keep the bolt head just free of the truck arm so it could rotate freely.

Leading wheel set

But then I found the truck do go down in a steep angle

Although maybe not very visible once hidden under the running board, I found the strange angle very obtrusive.

I gave it long and careful consideration and finally decided to cut the truck arm entirely. I made myself a new arm from 0.75 mm brass sheet and soldered it to the top of the truck. Now sat under only a slight  angle. Another job done!

The phosphor bronze strip soldered on top will make the truck a bit springy, reducing derailments.

At the left the little bush I made on my lathe. 1.3 mm inner diameter, 2.0 outer diameter and about 1.5 mm height.

Electric pick-ups

Next the wipers are installed.

I made little effort to document it in detail but if you want to know more please refer to the AD60 project where I described installation of the electrical pick-up more elaborately. In case of the NS5000 I deviated from this procedure in several ways.

• I soldered the wipers directly to the PCB, no rasing was needed.
• The entire board interfered with the main gear though (see photo left), so I had to raise it from its base by about 0.7 mm
• Instead of separate boards for each side I used only one which was electrically separated over its entire length.

Painting

The frame is now ready for painting. The slide bars and crossheads are masked en the axle bushes filled.

First the frame is sandblasted to roughen the brass..

Roughening will help the base coat stick to the brass.

I have a separate air blasting gun. Never use your normal airbrush for this!

Strictly speaking it is not sand that I use, but aluminium oxide. The photo on the left shows the effect of the roughening.

After blasting the frame is cleaned and degreased and masked again.

Provided with a base coat.

And semi-gloss black. After that the frame was given is semi-dull clear coat which toned down the gloss a little.

After a decent clear coat the gloss has seriously been toned down.

Before anything else it should be proven the whole setup with the motor, gearbox and running board would allow the boiler to slide over the gearbox. If this is not going to work this is the last chance to make a correction without extensive rework of everything that is to follow. So I more or less assembled the gearbox with the fourth axle in the frame cum running board and tried to assemble the boiler.

Success!

And this whole process for each single wheel, making sure that you store the wheel back in the very same compartment. Some 200 actions in all!

After all that you have a proud box of goodies

Final assembly

With all parts painted I can finally put everything together starting with the leading axle. The wheels of the leading axle are the most fiddly as it is a tight squeeze between the cylinders, slide bars and brake gear. Oh, FIRST clean the bearing surfaces of the wheel bearings.

After adding the coupling rod I spotted a problem. The crankpin of the leading axle would interfere with the slide bar!

This problem was of course created because I didn't not use the original crosshead and slidebar. The new crosshead slidebar take a lot more space. The interference would only occur if the axle was moved to its outmost position. There would be sufficient clearance if the axle was moved completely to the other side. I concluded I could solve this by a combination of two measures:

• Thinning the retaining nut that will keep the coupling rod on the crankpin from 0.8 mm to 0.4 mm
• Preventing sideways movement of the leading axle by adding washers of the appropriate thickness.

Chassis completed!

and rash decisions on the course of action if you feel like that. Let it rest, recover and ponder your options carefully.

I discussed the matter with a colleague of mine the following day. How is the cylinder attached? Glued with epoxy, I said rather gloomy. I had reason to. Epoxy is strong, very strong. With a pulling force of 300 kg/cm2 the chances of removing the cylinder without any further damage are minute. Okay, I remarked, I knew by experience that epoxy is sensitive to heat because parts have a tendency to fall off when soldered too close. Well, that opened options. My colleague sat up straight and said "Well, if you warm up the cylinder to say 100-120 degrees, not more, the epoxy will loosen up but not disintegrate. You might be able to give the cylinder the twist it needs, then let it cool down. If it is a good type of epoxy it might just settle down again. Been there, done it!".

Rail cleaner

Like the tender the leading truck had two white metal railcleaners. I disliked them as they where ugly and vulnerable, so I cut them off. I made myself an new pair from a strip of 0.5 mm nickel silver, a left-over from etch plates from another kit.

Bending them to suit was easier said then done. I needed several attempts to get them right. Above some scrap of previous attempts.